Originally Posted by
mtofell
I can't imagine where you dug of that statistic. Thousands (millions?) of years ago when there became too many people to reasonably keep track of, someone came up with the fantastic idea of names. Aside from people, we name things like vehicle brands, streets, buildings and just about everything else in the world that there are more than a few of. What if every person, street, building and city had two names? Or three, or four? The whole system just falls apart. Don't get me wrong, we're all free to have one, two, or seven names. My point is people just shouldn't be surprised when things go sideways.
Most of Latin America, save Argentina as the major exception, receives two last names at birth. It isn't a matter of option. It is a matter of what appears on official documents, and that's your name. It isn't a matter of freedom. For daily use, one is typically just, i.e., Jose Sanchez, or perhaps Jose Sanchez P (the first letter of the 2d last name). I've no idea what various countries do when there's only a single known parent.
As an example, and what will avoid the situation in the OP, I had a friend (in the USA), from Argentina in every manner except that the family went to Uruguay for mom to give birth, as to not have a child of Argentine nationality during the military dictatorship. So, this was someone who grew up in Argentina, used one last name his entire life ... well up to the point of moving to the USA, where he had to get used to the double last name, which appeared on everything - the passport, the eventual green card, the airline tickets, the airline FFPs, and so on ... and probably on the US passport, which he now holds.
The traditional US naming conventions, when compounded with the influx of other naming conventions to the US, has created a hodgepodge of methods, probably none of which were designed for exact name matching for passenger travel the way the systems were initially designed. "We" either put hyphens between the two last names, or put one of the two last names as the middle name, or just have two last names without a hyphen. Given the lack of consistency, and the technical requirements for what various institutions must now comply, I find it incumbent on each of us to determine what each institution requires for our custom.